This invention relates generally to evaluation arrangements for digital incremental transmitters or generators, and more particularly, to a digital incremental transmitter or generators which produces several angle-dependent sinusoidal voltages of substantially equal amplitude and which are shifted in phase with respect to one another by a predetermined phase angle.
Incremental transmitters can be designed as linear or rotary systems to operate, for example, on a photoelectric or a magnetic basis. It is a common feature of all such systems that the zero crossings, or interlinkages of the sinusoidal voltages, are evaluated and are utilized for imaging a distance. Since the produced sinusoidal voltages correspond to the travel of the transmitter system, typically, this can be done by converting the sinusoidal voltages into a number of meansurement pulses proportional to the number of period of the voltages. An illustrative magnetic type of digital transmitter is described in "Siemens-Zeitschrift", 1960, pages 669-671. A digital transmitter of the type which operates optically is described in the journal "Siemens Components", 1981, No. 1, pages 12 and 13.
It is a problem with known incremental transmitters that they do not provide measurement signals having sufficient resolution. Thus, it is desirable to increase the accuracy of distance measurements, particularly in situations where digital incremental transmitters are used in machine tools.
It is, therefore, an object of this invention to provide an evaluation arrangement wherein, in addition to counting periods of the sinusoidal voltages, intermediate values between such periods can be provided in the form of absolute values.